Control for phonographs



Oct. 6, 1936. c w R Z 2,056,372

CONTROL FOR PHONOGRAPHS Filed July 31, 1954 ATTORNEYS fiar/ar l1 Mum/ ix I Patented on. is, 1936 NMED STATES PATENT OFFICE (UQNTROL FOR PHONUGEAJPHS (Charles W. Schwartz, New York. N. Y. Application July 31, 1934, Serial No. 737,74? 0 2 @iaima. (@li. 274-1) The present invention relates broadly to phonegraphs and more especially to phonograph control mechanism which is operated electrically through the medium of a light sensitive electrical device such as a photo-electric cell.

It it well known in the art of phonographs to provide mechanically operated mechanism for automatic operation of the phonograph, as shown, for example, in United States Patent No. 1,465,909, August 21, 1923. Such automatic operation includes the placing of the pick-up in proper position upon different sized records at the beginning of the cycle of operations and either applying-an automatic brake to stop the machine at the end of the cycle of operations or lifting the record from the table and replacing it with a new record. Automatic mechanisms have also been developed for turning a record over to play both sides thereof before the record is replaced by a new one. Other automatic operations include constructions for automatically repeating the playing of a record.

The present invention comprises devices for controlling the various operations of an automatic phonograph such as for example the operations above outlined. The control providediby the present invention is actuated without physical contact with the record and preferably through the medium of a light beam falling upon a photoelectric cell connected in circuit with suitable amplifying means and suitablewlectrical means, whereby the automatic operations of the phonograph are controlled.

More specifically, the present invention comprises a photo-electric cell mechanism which moves coordinately with the pick-up arm. Pref-' erably, an electric light is mounted in a light tight chamber enclosing the record table, the pick-up, the photo-electric cell mechanism, and the supply of records for the automatic machine. The rays of light from the electric lamp fall upon a stationary white reflecting :strip which extends under-the record table that is slightly smaller than the smallest size record to be played.

When the machine starts its cycle of operations, the usual pick-up handling mechanism swings the pick-up arm and the photo-electric cell in an arc toward the center of the record in a raised position. The light falling upon the white reflecting strip activates the photo-electric cell circuit which continues the movement of the mechanism moving the pick-up arm in an arc toward and over the edge of the record. As soon as the photo-electric cell passes the edge of a record, the strong reflected light acting on the photo-electric cell is cut off by the edge of the common form of black disc record. This diminishes the current through the photo-electric cell to such an extent as to activate electrical devices which stops the swing of the arm, lowers the sound pick-up until the needle is resting in the record groove and the sound pick-up arm is now freed from mechanism which swings the arm, so that as the record rotates, the sound pick-up operates in the normal way. It will be observed that the operation of stopping the swing of the arm and lowering the needle into the groove is controlled by the edge of the record which intercepts the strong light rays coming from the reflected surface, beneath the record, to the photoelectric cell. Preferably, a sliding shoe controlled by the pick-up arm makes contact with a contact plate during the time of the swing of the pick-up arm over the edge of the record. As the pick-up arm swings toward the center of the record while playing, this shoe carried by the pick-up arm leaves the end of this contact bar, and prior to the end of the record being reached the shoe contacts with a second contact plate which is connected in a difierent electrical circuit. Inside of the last groove on the record is provided a reflecting surface carried by the record itself. This reflecting surface may comprise a circle of white or a spot of white such as would be produced by pasting a white paper wafer on the common formof black record. When the pick-up arm moves inward sufliciently to permit the photo-electric cell apparatus to pick up rays of light from the white spot on the record, the current through the photo-electric cell, the shoe and the second contact plate energizes electrical apparatus which lifts the pick-up arm from the record, swings it in a reverse direction outside of the zone of the largest record to be played and then the automatic operations of the machine continue to turn the record over or replace the record with a new record, or in semi-automatic machines to operate an electrical brake which shuts off the current to the motor and applies a brake to the record table.

The preferred construction comprises a small prism mounted adjacent the pick-up head in such manner as to reflect light back through a hollow tube to a photo electric cell mounted over the vertical axis of the pick-up arm.

Preferably, the present invention is adapted for use with black records common in the art. If a white record be used, then ablack strip is arranged adjacent or beneath the edge of the that it will be well understood by those skilled in the art.

n is to be understoodthat the disclosure is more or less diagrammatic of the preferred embodiment of the invention, but that the invention may be embodied in structures other than those specifically disclosed herewith and, therefore, the present disclosure is to be understood as illustrative and not in the limiting sense.

Fig. 1 is an elevational view showing the parts diagrammatically and illustrating the photoelectriccell, the pick-up mechanism and a supply of records as being mounted in a. light tight chamber which is illuminated 'by an electric light.

which illustrate the preferred form of light of the pick-up.

Fig. 3 is a plan view illustrating the reflecting surfaces with which the photo-electric cell cooperates.

Fig. 4 is a diagrammatic view illustrating the shoe and contact plates with which the photoelectric cell circuit may be effective to perform the operation desired.

Referring to the drawing and more especially to Fig. 1, a light tight chamber 1 may be enclosed by a suitable hinged top 2 to enclose the I record table 4 which carries the record I. A pick-up arm 0 is mounted in a suitable base 1 in such manner as to be movable vertically sufficiently to lift the sound pick-up l to clear the needle from the record grooves, and also to permit an oscillating movement of the arm parallel to the surface of the record I. A light pick-up 9. adapted to receive rays from the light It, is mounted upon the end of a light pick-up tube Iii which leads to a light tight chamber Ii in which is mounted a photo-electric cell l2.

Referring to Fig. 2, a light pick -up 9 preferably comprises a light tight head I l in which is mounted a prism II to receive the light rays falling upon a reflecting surface it, mounted stationary beneath the record table I at the edge thereof, in such manner that the light rays will be reflected by the prism down the light pickup tube III to the photo-electric cell 12. The

same path for the light rays applies when the spot I! on the record rotates past the bottom of the light pick-up head. A lens I. may be provided if desired to concentrate the reflected rays on the prism II. A suitable electric motor I! is adapted to rotate the record table 4 and is mechanically connected as indicated by the arrows in Fig. 1 with the record change mechanism and the record turn over mechanism 2| and the plck-up arm operating mechanism 22. These mechanisms are all operated under control of currents from the photo-electric cell l2.

Fig. 4 illustrates the stem 24 of the pick-up arm as carrying a contact shoe 25 when the pick-up arm occupies the radial'position as indicated hv the line 28'when the arm is outside of Fig. 2 is a detail view, showing parts in section,

the edge of a record. The contact shoe 2! is in engagement with and slides over a contact plate 21. This contact plate is connected with the pick-up arm operating mechanism, which swings the arm inwardly and lowers the sound pick-up head I so that sound pick-up needle engages the I arm is determined by the size of the record. In

Fig. 3, the edge 20 of the full line record indicates a large size record, whereas dotted lines 2! indicate a smaller record. It is to be understood, of course, that a single record at a time is on the record table, and with the large size record. the sound pick-up head will be lowered after a lesser degree of radial movement by the pick-up gm than is thecase with the smaller sized record Asthe pick up arm i moves inwardly toward the center of the record, the shoe 2| (Fig. 3) contacts with the stationary plate 20, establishing a circuit with the control mechanism for the record change and record turn over, so that when the light pick-up 8 reaches a position to receive a flash of light from the spot I! on the record. the current through the photo-electric cell changes and the change in the current actuates the automatic mechanism to perform whatever operations are desired after the record has been played. In a semi-automatic machine, this cur-' rent controls the brake 3| and at the same time. the current to the motor I is cut oil. In the full automatic machine, this current controls the these cycles may be considered as beginning at any place in the automatic operation. As a matter of convenience, the description herewith begins thesecycles at the swinging of the tone arm inwardly in the direction of the arrow 34 in Fig. 3 and at the end of the operations, the pick-up arm swings in the direction of the arrow 3! It is to be understood that the present invention is disclosed to those skilled in the art so that the invention may be used merely for the purpose ofapplying an automatic brake without the full automatic features or the invention may be utilized in connection with a full automatic phonograph to control the several operations which are performed by such a machine.

therefrom, a source of light, and light reflectin means carried by said record-and adapted to reflect light from said source of light to be effective on said photo-electric cell whereby the operation of said cell bysaid reflected light operates said control means.

2. In an automatic phonograph, the combination of means to rotate a record, a record carried by said means, a sound pick-up, a photoelectric cell, a source of light, a light pick-up movable with said sound pick-up and being adapted to transmit light to said photo-electric cell, mechanism to lower the sound pick-up to said record, and means to transmit light to said photo-electric cell when said light pick-up is outside 01 said record, the edge of said record intercepting the said light and causing said photoelectric cell to operate said mechanism to lower said sound pick-up to said record when the edge of said record intercepts said light.

' cmnms w. SCHWARTZ. 

